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Readme.md

SMTPE Controller

What is the SMTPE Controller

The SMPTE Controller is a wrapper for the Bitmovin Player which takes care of the conversion between a SMPTE Timecode and the actual video time

How to use the SMPTE Controller

1. include the javascript file:

<script type="text/javascript" src="js/FrameAccurateControls.js"></script>

2. Create the asset description object for your current asset:

new AssetDescription(assetName, sourceObject, frameRate, adjustmentFactor, framesDropppedEachMinute); the parameters for this object are as follows:

  • assetName: a string which identifies your asset, not used internally but useful for external access
  • sourceObject: A source Config object for the bitmovin player (e.g: {progressive: 'urlToMyVideo.mp4'})
  • frameRate: The frameRate of the video which is loaded
  • adjustmentFactor: OPTIONAL: If the framerate is not an integer value, this value is taken to calculate the difference between the SMPTE and the actual time (e.g.: 24 / 23.97 ~= 1.001). If omitted, will default to Math.ceil(framerate)/framerate
  • framesDroppedEachMinute: OPTIONAL If the video has frameHoles at every minute (excluding every 10minutes) specify the number here (29.97 has 2 frames dropped). If omitted, will default to 2 for a framerate of 29.97 or 29.98 and will default to 0 otherwise

3. Setup the controller with the given asset description:

new SmtpeController(playerInstance, assetDescription)

4. Use the provided functionality:

The SMPTE Controller offers the following "public" functions:

seekToSMPTE

Takes a SMTPE string or number as an input, converts it to a time and seeks to that time

getCurrentSmpte

Queries the current time of the player and converts it to an SMPTE representation in string form

step

Takes an integer input and steps that number of frames forward for positive input and backward for negative input

load

Takes a asset description and loads the new source while updating the internal asset description for the calculations

Utility

Additionally there is the class SmpteTimestamp which can come in handy for adding / subtracting Frames from a given SMPTE. You can set it up by providing a

  • String in the format of 'HH:MM:SS:FF' or
  • Number which will be interpreted fram back to front (matching the HH:MM:SS:FF pattern)
  • and an AssetDescription to handle the internal conversions

Example Usage:

    const smpte = new SmpteTimestamp('00:30:00:01', assetDescription);
    smpte.addFrame(5); // there is an optional boolean parameter which allows supression of missing frames in the calculation 
    player.seek(smpte.toAdjustedTime());